When I try to open a local html file with space in the filepath firefox fails to open it. Here are steps to reproduce it on Ubuntu MATE 17.10 with firefox (all upgraded to latest versions from standard repositories).
mkdir ‘test ing’
cd ‘test ing’
echo ‘test’ > test.html
then right-click test.html file to open in firefox.
Instead of opening the file, a new firefox window will open with two tabs. One with path ‘file:///home/$USER/test’ and another with path ‘ing/test.html’ that the browser will them try to match with some url (https://www.ing.com/test.html) that will give 404.
One tab with path ‘file:///home/$USER/test%20ing/test.html’ (I 'm assuming here that firefox will handle the space like chrome does) showing the file as intended.
I have opened a bug report about this at Mozilla here. If you also experience this please help them verify the problem. I am not sure if it is more firefox related or more MATE related though.
Can people here test to see if they have this behavior?